Originally Posted by boredom.is.me
With the 25/12, you need serious rpms. The 5800kv isn't going to do any better than a 1015 11500kv. If you were able to get the 5800kv on 5s (which isn't going to happen), then you might see something worth it. Turboace has a 16800kv 12mm inrunner - Turbo Ace 31714. (I have no idea where to get it though.)
You will also need to use a clipped 40mm rotor, or a trimmed 7-blade 27mm rotor.
So what kind of setup do you believe is ideal for your 25/12? For this plane you need a setup that will give you at least 45 grams or so of thrust for 1:1. This assumes that you will be around that weight after carving out a bunch of foam and putting in lightweight electronics.
A 25/10 seems good enough. Here is Nitro's set up with 47 grams thrust: